java.util.stream

Class StreamSupport


  • public final class StreamSupport
extends Object
    Low-level utility methods for creating and manipulating streams.

    This class is mostly for library writers presenting stream views of data structures; most static stream methods intended for end users are in the various Stream classes.

    Since:
    1.8

    • Method Detail

      • stream

        public static <T> Stream<T> stream(Spliterator<T> spliterator,
                                   boolean parallel)
        Creates a new sequential or parallel Stream from a Spliterator.

        The spliterator is only traversed, split, or queried for estimated size after the terminal operation of the stream pipeline commences.

        It is strongly recommended the spliterator report a characteristic of IMMUTABLE or CONCURRENT, or be late-binding. Otherwise, stream(java.util.function.Supplier, int, boolean) should be used to reduce the scope of potential interference with the source. See Non-Interference for more details.

        Type Parameters:
        T - the type of stream elements
        Parameters:
        spliterator - a Spliterator describing the stream elements
        parallel - if true then the returned stream is a parallel stream; if false the returned stream is a sequential stream.
        Returns:
        a new sequential or parallel Stream

      • stream

        public static <T> Stream<T> stream(Supplier<? extends Spliterator<T>> supplier,
                                   int characteristics,
                                   boolean parallel)
        Creates a new sequential or parallel Stream from a Supplier of Spliterator.

        The Supplier.get() method will be invoked on the supplier no more than once, and only after the terminal operation of the stream pipeline commences.

        For spliterators that report a characteristic of IMMUTABLE or CONCURRENT, or that are late-binding, it is likely more efficient to use stream(java.util.Spliterator, boolean) instead.

        The use of a Supplier in this form provides a level of indirection that reduces the scope of potential interference with the source. Since the supplier is only invoked after the terminal operation commences, any modifications to the source up to the start of the terminal operation are reflected in the stream result. See Non-Interference for more details.

        Type Parameters:
        T - the type of stream elements
        Parameters:
        supplier - a Supplier of a Spliterator
        characteristics - Spliterator characteristics of the supplied Spliterator. The characteristics must be equal to supplier.get().characteristics(), otherwise undefined behavior may occur when terminal operation commences.
        parallel - if true then the returned stream is a parallel stream; if false the returned stream is a sequential stream.
        Returns:
        a new sequential or parallel Stream
        See Also:
        stream(java.util.Spliterator, boolean)

      • intStream

        public static IntStream intStream(Spliterator.OfInt spliterator,
                                  boolean parallel)
        Creates a new sequential or parallel IntStream from a Spliterator.OfInt.

        The spliterator is only traversed, split, or queried for estimated size after the terminal operation of the stream pipeline commences.

        It is strongly recommended the spliterator report a characteristic of IMMUTABLE or CONCURRENT, or be late-binding. Otherwise, intStream(java.util.function.Supplier, int, boolean) should be used to reduce the scope of potential interference with the source. See Non-Interference for more details.

        Parameters:
        spliterator - a Spliterator.OfInt describing the stream elements
        parallel - if true then the returned stream is a parallel stream; if false the returned stream is a sequential stream.
        Returns:
        a new sequential or parallel IntStream

      • intStream

        public static IntStream intStream(Supplier<? extends Spliterator.OfInt> supplier,
                                  int characteristics,
                                  boolean parallel)
        Creates a new sequential or parallel IntStream from a Supplier of Spliterator.OfInt.

        The Supplier.get() method will be invoked on the supplier no more than once, and only after the terminal operation of the stream pipeline commences.

        For spliterators that report a characteristic of IMMUTABLE or CONCURRENT, or that are late-binding, it is likely more efficient to use intStream(java.util.Spliterator.OfInt, boolean) instead.

        The use of a Supplier in this form provides a level of indirection that reduces the scope of potential interference with the source. Since the supplier is only invoked after the terminal operation commences, any modifications to the source up to the start of the terminal operation are reflected in the stream result. See Non-Interference for more details.

        Parameters:
        supplier - a Supplier of a Spliterator.OfInt
        characteristics - Spliterator characteristics of the supplied Spliterator.OfInt. The characteristics must be equal to supplier.get().characteristics(), otherwise undefined behavior may occur when terminal operation commences.
        parallel - if true then the returned stream is a parallel stream; if false the returned stream is a sequential stream.
        Returns:
        a new sequential or parallel IntStream
        See Also:
        intStream(java.util.Spliterator.OfInt, boolean)

      • longStream

        public static LongStream longStream(Spliterator.OfLong spliterator,
                                    boolean parallel)
        Creates a new sequential or parallel LongStream from a Spliterator.OfLong.

        The spliterator is only traversed, split, or queried for estimated size after the terminal operation of the stream pipeline commences.

        It is strongly recommended the spliterator report a characteristic of IMMUTABLE or CONCURRENT, or be late-binding. Otherwise, longStream(java.util.function.Supplier, int, boolean) should be used to reduce the scope of potential interference with the source. See Non-Interference for more details.

        Parameters:
        spliterator - a Spliterator.OfLong describing the stream elements
        parallel - if true then the returned stream is a parallel stream; if false the returned stream is a sequential stream.
        Returns:
        a new sequential or parallel LongStream

      • longStream

        public static LongStream longStream(Supplier<? extends Spliterator.OfLong> supplier,
                                    int characteristics,
                                    boolean parallel)
        Creates a new sequential or parallel LongStream from a Supplier of Spliterator.OfLong.

        The Supplier.get() method will be invoked on the supplier no more than once, and only after the terminal operation of the stream pipeline commences.

        For spliterators that report a characteristic of IMMUTABLE or CONCURRENT, or that are late-binding, it is likely more efficient to use longStream(java.util.Spliterator.OfLong, boolean) instead.

        The use of a Supplier in this form provides a level of indirection that reduces the scope of potential interference with the source. Since the supplier is only invoked after the terminal operation commences, any modifications to the source up to the start of the terminal operation are reflected in the stream result. See Non-Interference for more details.

        Parameters:
        supplier - a Supplier of a Spliterator.OfLong
        characteristics - Spliterator characteristics of the supplied Spliterator.OfLong. The characteristics must be equal to supplier.get().characteristics(), otherwise undefined behavior may occur when terminal operation commences.
        parallel - if true then the returned stream is a parallel stream; if false the returned stream is a sequential stream.
        Returns:
        a new sequential or parallel LongStream
        See Also:
        longStream(java.util.Spliterator.OfLong, boolean)

      • doubleStream

        public static DoubleStream doubleStream(Spliterator.OfDouble spliterator,
                                        boolean parallel)
        Creates a new sequential or parallel DoubleStream from a Spliterator.OfDouble.

        The spliterator is only traversed, split, or queried for estimated size after the terminal operation of the stream pipeline commences.

        It is strongly recommended the spliterator report a characteristic of IMMUTABLE or CONCURRENT, or be late-binding. Otherwise, doubleStream(java.util.function.Supplier, int, boolean) should be used to reduce the scope of potential interference with the source. See Non-Interference for more details.

        Parameters:
        spliterator - A Spliterator.OfDouble describing the stream elements
        parallel - if true then the returned stream is a parallel stream; if false the returned stream is a sequential stream.
        Returns:
        a new sequential or parallel DoubleStream

      • doubleStream

        public static DoubleStream doubleStream(Supplier<? extends Spliterator.OfDouble> supplier,
                                        int characteristics,
                                        boolean parallel)
        Creates a new sequential or parallel DoubleStream from a Supplier of Spliterator.OfDouble.

        The Supplier.get() method will be invoked on the supplier no more than once, and only after the terminal operation of the stream pipeline commences.

        For spliterators that report a characteristic of IMMUTABLE or CONCURRENT, or that are late-binding, it is likely more efficient to use doubleStream(java.util.Spliterator.OfDouble, boolean) instead.

        The use of a Supplier in this form provides a level of indirection that reduces the scope of potential interference with the source. Since the supplier is only invoked after the terminal operation commences, any modifications to the source up to the start of the terminal operation are reflected in the stream result. See Non-Interference for more details.

        Parameters:
        supplier - A Supplier of a Spliterator.OfDouble
        characteristics - Spliterator characteristics of the supplied Spliterator.OfDouble. The characteristics must be equal to supplier.get().characteristics(), otherwise undefined behavior may occur when terminal operation commences.
        parallel - if true then the returned stream is a parallel stream; if false the returned stream is a sequential stream.
        Returns:
        a new sequential or parallel DoubleStream
        See Also:
        doubleStream(java.util.Spliterator.OfDouble, boolean)